Carburetor



Aug. 19 1924.

C. F. JOHNSON CARBURETOR Filed Dec. 21. 1916 HHM fz i

MGTHLS HHVING DIFFERENT CDEFF/CIENTS u willl flnlllllu. lll'.

ATTORNEY vPatented Aug. 19, 1924.

.STATES CHESTER r. JoHNsoN, ornnrao-IT, Mrcmea'n.

Application filed December 21, 1916. Serial No. 138,145.

To all whom t may concern:

Be it known that I, CHESTER F. JOHNSON, a citizen of the United States,and resident of Detroit, Wayne County, State of lWichigan, have inventedcertain newand useful Improvements in Carburetors, of which thefollowing is a specification.y l

This invention relates to carburetors, or fuel mixin devices.

Une of t e objects of this invention is to provide simple, improved, andefficient quallity regulators for fuel mixing devices.

Another object of my invention is toprovide a carburetor, with improvedmeans for regulating the flow of fuelpto the mixing chamber underpre-determined conditions.

In the form illustrated, the various objects are obtained by varying thepressure of the air on the liquid within the 'fuel chamber.

In general, my invention involves the use of a carburetor comprising amixing chamber, a fuel chamber, therefor, and a nozzle through whichfuel from said fuel chamber is discharged into said mixing chamber; andincludes means for admitting pressure to the surface of the fuel within`the chamber in which it is contained to thereby increase the pressureon the fuel as a throttle valve 3@ for controlling the flow ofcombustible mixture to the engine is opened; thus increasing therichness of the mixture and accelerating the motor with which thecarburetor is connected;I said throttle valve and said means foradmitting pressure to the fuel in the fuel chamber being connectedtogether s o as t operate in unison. This means is so arranged thatafter the throttle is opened wider and has come to rest in a newposition 40 the pressure upon the fuel is automatically reduced, wherebya satisfactory mixture for each particular position of the throttle willbe secured.

The various objects, purposes, constructions and principles involved,will more clearly appear from the following description, taken inconnection with the accom- 'panying drawin s, which' form a part of thisspecification, an in which:

Figure I is a side elevation with portions broken away, of a carburetorembodying a preferred form of my invention;

Figure II is a vertical section, substantially on the line 2--2 ofFigure I; and

Figure III is a fragmentary vertical secing chamber on a shaft 18, onthe end of which may be secured an `operating arm 19.

Arranged below and suitably secured to the carburetor body 10, is a fuelchamber 20. 'Ihe fuel chamber comprises a float bowl or shell 21, acover member 22 having an intake ort 23, adapted to be controlled by aneed e valve member 24, and a float 25, suitably pivoted to the covermemberv as at 26. It will be noted that the' cover member l22 is formedwith a depression 27, in the center of which is formed a fuel nozzle 28,adapted to be fed from the interior of the chamber 20. Suitably mountedbetween the carburetor body 10 and the cover member 22, is a plate 29provided with a Venturi tube 3Q. The fuel chamber 20 is provided with avent or relatively small air port 31 arranged above the normal level offue therein.

It will also be noted that the carburetor is provided with a primary airport 32, formed in the cover member 22, and that the auxiliary air port13, if any, is in direct communication with the mixing chamber .11, bymeans of the laterally .extending portion 12 of the carburetor body.

A conduit, or air'passage 33, is provided, connectin the fuel chamberand the mixing chamber y means of the ports 34 and 35 respectively. Itwill be noted that the vacuum within the mixing chamber 1,1, will 100 bymeans of the conduit 33, be communicated to the fuel chamber 20, thustendmg to normally 'reduce the eect of atmospheric pressure on the fuelwithin the chamber', v and thereby -retarding the flow of. fuel 105through the nozzle 28. I

The previously described parts and-passages of the carburetor, are soproportioned and adjusted, that with the throttle 1n any yfixedposition, such as .for idling or la- 110 boring `of the motor, or highspeed light running conditions, the mixtureproduced 1s ade uate andsufficient for such conditions.

ile the previously described construction and" arrangement of parts maybe sufficient for fixed running conditions, it is desired to produce, attimes, a richer mixture such as when the throttle valve 17 is openedquickly for accelerating the motor. This means may be in the form of arelatively large air vent or port 36, formed in the cover member 22, ofthe fuel chamber 20. This port may be controlled by a valve member 37having a piston or plunger portion 38 arranged in a cylindrical member-39, having a plvotal connection as at 40, with an arm 41, fixed to thethrottle shaft 18. The plung ger portion 38 of the valve member 37, isso. dimensioned that lit fits rather closely in the cylinder 39.

It will be noted thatwith the throttle in closed position, the-valvemember 37 will rest on, and render the port 36 inactive. If the throttlevalve 17 is opened quickly, it will simultaneously lift the'cylinder 39,and anyy tendency for the valve member 37 to remain in its closedposition will be momentarily overcome bythe suction between the top ofthe piston 38 and the cylinder39, thus opening the port 36 anddecreasing the tendency of the air passage 33 to retard the flow of fuelthrough thenozzle 28, and

lriereby accelerating the flow of fuel 4there- A spring 42, may bearranged between the end of the piston lprtion 38 and the cylinder 39,for gradua y relieving the vacuum within the cylinder and returning thevalve member 37 to its seat. The return movement of the valve member 37to its seat will, of course, be governed by the amount of clearanceprovided between the piston portion and the cylinder 39. If theclearance is great enough, there will, of course, be no necessity forthe spring 42, as gravity will return the valvemember 37 to its seat.This clearance may be made variable by having the piston and cylinderformed ofv metals having different coefficients of expansion, thusautomatically compensating for variations of climatic or temperatureconditions.

It will be understood from the foregoing description, that the port 36isi-normally closed by itsvalve, regardless of the throttle positlon,thereby prducinga certain quality of mixture, but should it be desiredto accelerate'the motor by throwing the throttle 17 open wider, thevalve 37 would be lifted by the throttle arm 41, and the cylinder 39,after which the valve is slowly returned to litsseat, and, of course,the vflow of fuel through the nozzle 28 will be accelerated during theperiod the port 36/is open, with the *result that the mixture is'enriched for providing 'an accelerating mixture.

While I have described and will specifembodiment of my invention, itwill be obvious to those skilled in the art, that various modificationsand changes may be made without departing from the spirit and scopethereof. Y

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a carburetor for internal combuston engines, a fuel chamber, amixing chamber, a fuel passage'leading from the fuel chamber tothemixing chamber, a throttle valve, and means independent of the suctionof the engine and yieldingly connected with said Vthrottle 'valveforadmitting pressure to the surfacevof the fuel in said chamberwherebythe How of fuel through said passage is controlled.

ling said port, a mixing chamber, a fuel passage leading frorn the fuelchamber to the mixing chamber, a throttle valve, and means comprising anextensible connection for operating said first Vvalve with said throttlevalven y 3. In a carburetor,a first passage through which air flows onits way to the en ine, a fuel chamber arranged to supply lel to saidpassage, a second passage leading from a point in the fuel chamber abovethe level of fuel therein to said first passage and tending to establishsub-atmos heric pressure in said chamber, a thrott e valve for the firstpassage, and means for momentarily increasing and afterwards reducingthe pressure in the fuel chamber when the throttle valve is moved invone direction;

4. In a carburetor comprising a fuel chamber` a mixin chamber connectedtherewith, and a thrott e valve for controlling the How of fluid throughthe mixing chamber, an `air port leading to said fuel chamber above thelevel of the fuel therein, a valve for saidvport, and means connectingsaid two valves so constructed and arranged that the second mentionedvalve is opened as the throttle valve is moved quickly in one direction,and is thereafter automatically gradually closed independently of thethrottle valve. l

5. In a carburetor, the combination with a fuel chamber having an-airport, a. valve for said port, a mixture passage supplied with fuel fromsaid chamber, a throttle valve for said passage, and interconnectedmeans, independent of the suction of" an engine to which thecarburetormay be connected, for

simultaneously opening said valves. said'V L communicating therewith, aport for admitting air to the fuel chamber, a passage connecting thefirst named passage to the fuel chamber above the level of the fueltherein, and means acting to normally close the port, said meansincluding a cylinder and piston construction arran ed to open the portat will and to therea ter gradually close said 4 port. p

7. In a carburetor, a passage through which air flows to the engine, afuel chamber communicating therewith, a port for admitting air to saidchamber, a passage connecting said lirst named passage to the upper partof said chamber to reducethe pressure therein when the engine isrunning, a valve for said port, a throttle for the first named passage,and a temperature responsive connection between 'said throttle and saidvalve.

In testimony whereof I aix my signature.

CHESTER r.y JOHNSON.

